Certain measurements of physical magnitudes can be represented by an electric current. It may additionally be necessary to integrate this current with respect to time, for example:                when a sensor provides a measurement in the form of an electric current and when, for various reasons, one wishes to integrate this current over a given time period, this is notably the case in the field of visible and infrared imaging;        when a sensor provides a measurement in the form of a current pulse, of finite duration, whose integral with respect to time represents a finite charge quantity, this is notably the case in gamma and X-ray imaging;        generally, when a datum or a physical magnitude is represented in electrical form by the potential difference across the terminals of a capacitance.        
In all these cases, in general the measurement of integrated current must be digitized in order to be utilized. The digitized value can then be utilized by digital processing or microprocessor-based means.